The Effect of Bolus Viscosity on Laryngeal Closure in Swallowing: Kinematic Analysis Using 320-Row Area Detector CT.

Faculty of Rehabilitation, School of Health Sciences, Fujita Health University, 1-98 Dengakugakubo, Kutsukake, Toyoake, Aichi, 470-1192, Japan, .
Dysphagia (Impact Factor: 1.6). 06/2012; 28(1). DOI: 10.1007/s00455-012-9410-4
Source: PubMed

ABSTRACT The present study examined the effect of bolus viscosity on the onset of laryngeal closure (relative to hyoid elevation), the duration of laryngeal closure, and other key events of swallowing in ten healthy volunteers. All volunteers underwent 320-row area detector computed tomography swallow studies while swallowing 10 ml of honey-thick barium (5 % v/w) and thin barium (5 % v/w) in a 45° reclining position. Three-dimensional images of both consistencies were created in 29 phases at an interval of 0.10 s (100 ms) over a 2.90-s duration. The timing of the motions of the hyoid bone, soft palate, and epiglottis; the opening and closing of the laryngeal vestibule, true vocal cords (TVC), and pharyngoesophageal segment; and the bolus movement were measured and compared between the two consistencies. The result showed differing patterns of bolus movement for thin and thick liquids. With thin liquids, the bolus reached the hypopharynx earlier and stayed in the hypopharynx longer than with thick liquids. Among events of laryngeal closure, only the timing of TVC closure differed significantly between the two consistencies. With thin liquids, TVC closure started earlier and lasted longer than with thick liquids. This TVC movement could reflect a response to the faster flow of thin liquids. The results suggest that bolus viscosity alters the temporal characteristics of swallowing, especially closure of the TVC.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Swallowing is a complex biomechanical process. In this review, several different techniques for measuring swallowing physiology are described, and limitations of each instrumental perspective are discussed. The techniques discussed include videofluoroscopy, endoscopy, 3D dynamic CT imaging, ultrasound, electromagnetic articulography, electromyography, lingual and pharyngeal manometry, electropalatography, airflow measurement and swallowing acoustics/accelerometry. It is hoped that this review will inform scientists in the food oral processing field regarding methods that may be useful for capturing relevant features of swallowing behavior across different food textures and liquid consistencies. Likewise, it is hoped that the delineation of current gaps in knowledge will reveal topics of shared interest for swallowing and food oral scientists as a first step towards future collaboration.
    Journal of Texture Studies 11/2014; · 1.05 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Conservative estimates suggest that dysphagia (difficulty swallowing) affects approximately 8 % of the world's population. Dysphagia is associated with malnutrition, dehydration, chest infection and potentially death. While promising treatments are being developed to improve function, the modification of food texture and liquid thickness has become a cornerstone of dysphagia management. Foods are chopped, mashed or puréed to compensate for chewing difficulties or fatigue, improve swallowing safety and avoid asphyxiation. Liquids are typically thickened to slow their speed of transit through the oral and pharyngeal phases of swallowing, to avoid aspiration of material into the airway and improve transit to the esophagus. Food texture and liquid modification for dysphagia management occurs throughout the world. However, the names, the number of levels of modification and characteristics vary within and across countries. Multiple labels increase the risk to patient safety. National standardization of terminology and definitions has been promoted as a means to improve patient safety and inter-professional communication. This article documents the need for international standardized terminology and definitions for texture-modified foods and liquids for individuals with dysphagia. Furthermore, it documents the research plan and foundations of a global initiative dedicated to this purpose.
    Current physical medicine and rehabilitation reports. 12/2013; 1:280-291.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Although coordination and timing of swallowing have often been investigated by using discrete timing events such as the onset, peak, and duration of specific motions, the sequence and duration of swallowing events cannot represent the coordination of the swallowing mechanism quantitatively. This study aimed to apply a cross-correlation analysis of the motions of the hyolaryngeal structures during swallowing as an objective method for measuring the coordination and timing of the motions. Forty healthy subjects swallowed 2 and 5 ml of diluted barium solution (35 %) and 5 ml of curd yogurt under videofluoroscopy. Hyolaryngeal motions in videofluoroscopic images were digitized using the motion analysis system. The time series of the horizontal and vertical hyoid motion, the laryngeal elevation, and the angle of the epiglottic tilt were analyzed using cross-correlation at each 1/60-s time lag. The results showed high and consistent cross-correlations between hyolaryngeal motions during swallowing in most of the subjects regardless of age and bolus type. The horizontal hyoid motion and laryngeal elevation were more strongly correlated with the epiglottic tilt than the vertical hyoid motion, which might suggest the mechanism of the epiglottic tilt during swallowing. The bolus volume and viscosity affected the correlation coefficients and time lags between the hyolaryngeal motions, particularly those related to the epiglottic tilt. The results suggest that cross-correlation analysis may be used for measuring the coordination and timing of swallowing. Further studies using cross-correlation analysis of additional physiological factors related to swallowing or pathological conditions are warranted.
    Dysphagia 07/2014; · 1.60 Impact Factor